| | | 1 - "The earth has warmed, is warming, and will continue to warm."
Established
The first part is. The 2nd depends on the time frame and data series you are considering. The third part is a reasonable belief given the evidence but isn't established.
2 - "This is overwhelmingly because of human emission of CO2 (and to a lesser extent other greenhouse gases)"
established
It is established that CO2 is a greenhouse gas (as are some other gasses emitted because of human activity but CO2 should have the most impact), and has a net warming effect Its not firmly established exactly how much of past warming was due to CO2 changes (predominately but not totally because of human emissions) and how much was due to other reasons.
3 - "Warming like this has never happened in human history"
established
The evidence for some other periods is uncertain and disputed. Again a reasonable belief given the evidence, but not quite firmly established.
4 - "If things are not massively changed the result will be globally catastrophic."
yup
Here you go well beyond "reasonable belief but not firmly established", to "unlikely"
5 -" If human activity that produces greenhouse gasses is massively cut very soon. Then the crisis can be averted"
Too late to avert, since it's upon us, but not too late to avoid making it worse.
The uncertainty is much greater then that. Even in the unlikely event that their will be a massive global catastrophe because of human emission of CO2, there would be a large degree of uncertainty about both the "to late to avert", and the idea that reasonably possible changes could make a big difference in how bad the disaster would occur.
6 - "Human greenhouse gas emissions can be rapidly cut, "
FF-free by 2050 doesn't strike me as very rapid
For such a large change that is very rapid. It likely isn't possible without more harm then would be caused by warming by that CO2 if it had been emitted. And in terms of real practical political and economic reality, probably isn't possible at all, even if we drop all care about economic harm and stomp down on the political opposition. |
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